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On the progress and present state of the electric telegraphs
.Electric Telegraphs.
61
their attendance at ye time and place aforesaid; and it was further ordered that both partys have liberty to bring with them councill learned if they ])lease."
On the Progress and Present State of the Electric Telegraphs.* The explanation ,~-hich we gave ia our last Journal of the remarkable ~,nprove ments,, in the electric, tele gra.ph has attracted. ,very general attenlioz~, and the prospectus of the Umversal Electric ~lelegraph Company is now before the public, under a highly influential directory. As the subject is one of intense scientific interest, as well as of great national importance, we this day devote our columns to a further elucidation (if the progress and present state of that art. The electric telegraphs at present in operation may be divided into four elasses~First, those the pointers o~"indices of which move in front of dials bythe agency of the electric current inside or beneath them. Second, those the indications of which'are marked by the breaking up of a continuous line, and dividing it in~,oshort and long lines and spaces. Third, telegraphs showing letters, in which a pointer on a dial is made, by the agency of' electricity beneath or behind the dial, to give motion to a wheel governed by an escapement, and then to a hand in front of the dial. Fourth, letter or type-printing telegraphs, in which the letter or metallic type is brought to a position, and while there made to impinge on paper, or otherwise to give the impression. In the first class may be placed Cooke's and Wheatstone's telegraph, as used by the Electric Telegraph Company ; Itighton's , as used by the British Telegraph Company ; Itenley's and t oster's, as used by theIrish Magnetic Telegraph Company; Deering's, as used by the Submarine and European ~lel%,raph • O" Company ; and Allen's, as proposed to be used by ~he United Kingdom Telegraph Company. The second class embraces Bain's Telegraph, as used by the General Telegraph Company on a few of their principal lines, the paper on which the line is made being ia {his plan saturated with a metallic solution ; and Morse's, used in America, in which plain paper is employed, and which is now introduced by the British Telegraph Company on some of their lines, in preference to the pointer telegraph of Itighton, previously.referi~ed to. To these pay be added Bakewell's copying telegraph, winch, oy a series ot oroK.en lines placed one under the other, leaves the letter indicated, or rather omitted, by the spaces in the broken lines. In the third class may be placed Wheatstone's orioinal~ teler,raoh,~ , now belo~ing, v to the Electric Telegraph Company; Highton's, to the Briush 2elegraph Company; Gamble and Nott's, to the Electric Telegraph Company; Allen's, proposed to be used by the United Kingdom Telegraph Company; and others of less note. The dial system is, however, subject to this objeelion, that when the hand is standing at O, or what ought to be the starting point, it must, in order to spell a word, traverse or pass over other letters on the dial, yarying in distance according to the position of the word in the alphabet, and this it must do in spelling every word. Under ~' :From the London tlailway and Commercial Gazette, No. 952. Vo~.. X X V I I . ~ T t I I a D S~:~I~s,--No. 1.--Ja-'~uaxt, 1854.
6
6"2
.Mechanics, .Physics, and Chemist~'y.
the fourth class, the letter or type-printing telegraphs~ must be classed Brett's telegraph, belonging to the Submarine Telegraph Company, and House's, as in use in Amertca. The advantages of tlm new telegraph now proposed to be worked by the Universal Electric I elegraph Company over the telegraphs comprised in the first class are, that the signals or indications corresponding with the movement of the needles or pointers are made and marked legibly and distinctly, so rapidly that needles or pointers movin/ at the same rate could not be read by the most experienced operator. To this must, of course, be added the incalculable advantage of having the communication fixed and recorded on paper, instead of the mere flickering and fleeting movements of pointers. In the first instance, the operation may be carried on with a rapidity never contemplated in former telegraphs ; and in the second instance, the communication is permanent, and may be kept and proved in years after, like a short-hand writer's note, by any person master of the alphabet. A further marked sut~eriority consists in this--that in all telegraphs worked on the .principle of the first class, one operator is required in the first instance to read the motions of the pointers, and another at the same time to write them do~vn. In the new telegraph only one operator will be required, who will write down the several communications as they appear on the paper before him, and at the same time ; and thus there is a saving of one-half of the staff of operators. Telegraphs of the second class presented certain advantages--namely, rapidity, simplicity, and clearness of character. Bain's telegraph consisted of an iron pointer or stilus, pressed upon paper saturated and kept moist with a metallic solution. Marks are made upon the paper by the passage of the electric current from any distance through the stilus, and consequently through paper in its passage to lhe earth, acting upon or decomposing both the iron stilus and the solution on tile paper, and leaving alter it a dark mark. By this system it is evident that if the current is continuous through the wire, and the paper be drawn regular]y under the stilus, the result will be a dark line ; and if the current be passed irregularly and in pulsations, the line will be broken ; anti when the current ceases to pass along the wire, no mark whatever will appear. The principle of Morse's telegraph is nearly similar; but instead of a metallic pointer acting chemically, and being in its turn chemically acted upon, this invention is a mechanical telegraph, giving precisely similar results. A lever is used, being depressed at one end and raised at the other, while the current is passing through a magnet at one extremity. A pin is placed at the raised end of the lever, which scratches the paper on contact, while the current is l~assine, and the ~)aner movino, under the pm end of the lever. If the current ~s'passmg m t;ulsations,~the line is of course broken ; and when the current ceases to pass through the magnet, the line also ceases to appear. The only form of cipher or character which these telegraphs can represent is short or long lines~thus one short line may be called a, two short lines b, three short lines c, one long line D, two l~], three I#, so that to obtain 30 lettersor conventional signs, a greater number of long or short lines, or of both, have to be used. Increased rapidity will be secured by the new telegraph from the eircum-
~lectric Telegraphs.
63
stance, that instead of one short pulsation or dot, representing one letter, it will represent two letters, two will represent four, and so on ; and the same with continuous lines, so that with one, two, and three short pulsa., fions, and one, two, and three long pulsations, instead of making, as in 5:[orse and Bain's telegraphs, only six signs or letters, twenty-eight or more can be made, thus exeeeding the whole alphabet. It is evident, therefore, that instead of seeking other and longer combinations, as must be the case with the other telegraphs, the new company will be enabled to make all necessary combinations with the newly invented telegraph. Simplicity is secured by the new telegraph using paper that does not require any preparation, either chemical or mechanical, and that is only one-fourth of the expense of that required for Morse's telegraph. Clearness is obtained by the length and size of the distinguishing characters; for instance, one short pulsation of either Morse's or Bath's telegraph makes a dot or short line of about one-sixteenth of an inch long. In the new telegraph, a similar pulsation will make a character resembling a V, or angular or arrow-pointed form, having a base about the same length as the short line above specified, and a depth in the sides of an eighth of an inch, being therefore much more distinct. Another sut)eriority, known chiefly or only to telegraphers themselves, exists ; for in consequence of the characters presenting a continuous line, and there being only suiiicient distinguishing space left between them, they are not subject to the same defects, or likely to be read wrong, as constantly occurs m other telegraphs. No comparison need be made with the third class: they are admitted to be so inferior to telegraphs of the tirst and second class; depending on an irregular vibrating movement, the slightest casual irregularity or fluctuation entails the certainty of mistake in the entire word or message. The advantages of the improved system over telegraphs of the fourth el.ass are numerous. Although the public are apt to be attracted and. misled by the supposed benefits to be derived from the telegraphs printing the letters in Roman and other readable type, there are more imperfections attending this class than are generally supposed, and which are known only to operators themselves. They depend, like those of the third class, upon a fluctuating movement of an escape-wheel, governed by an escapement, which may possibly, and often does, pass one too many, or one too few. As the type is a fixture on the wheel motion, when such a mistake occurs, the receiver must know from the sense or nonsense of what he receives by the telegraph that something is ,a,rong with the machinery ; by no means an uncommon occurrence. Perhaps the best, or, notwithstanding its extreme complexity, the most efficient telegraph of flats class, is the American one of Mr. Itouse. Even when used under his own eye, it appears to be liable to serious mishaps, and would seem to be inferior in rapidity to either Morse's or Bath's telegraphs, which are of the second class. In the telegraphs of the fi)urth class, the current transmitted along the wire has to bring into operation certain complicated apparatus or m a ' chinery, upon the correct movement of which depends the accurate transmission of the message. The superiority of the Universal Compa-
64
.Mechanics, Physics, and Clzeraistry.
ny's Telegraph over the last mentioned class consists in simplicity, corn. paralively less cost, more rapid!ty, and no necessity tor correcting errors, au even a mistake ia one letter Is not entailed on the one that follows it.
Ocean Steamers.* The discussion upon the Paper on "Ocean Steamers," by Mr. Andrew ]h:uderson, Assoc. Inst. C. E., was commenced by quoting fi'om an article in the Edinbt~rffhJo~r~zal,by Professor Tennant, of St. Andrews, the dimensions of some of the la,'ge ships built by the ancients; whence it appeared that a ship, constructed by Ptolommus Philopater, was 420 feet long, 5fJ feet b~oad, and 7"2 feet high from the keel to theprow; and was manned by fi~u," thousand rowers, four hundred servants, and two thou.~md eight hundred and twenty marines. Hiero, King of Syracuse, caused to he built, by Arehias, the Corinthian shipwright, under the supervision ,~f Archimedes, a vessel which appeared to have been armed for war, and sumptuously fitted for a pleasure yacht, and yet was ultimately used to ,:arty corn; the dimensions were not recorded, but as there were twenty banks of oars, and three masts,--the timber for the mainmast, after being in vain sought for in Italy, being brought from England,--and the cargo was sixty thousand measures of corn, besides vast quantities of provisions, &c., for the crew, the dimensions must have exceeded those of any ships cJf the present day; indeed, Hiero, finding that none of the surrounding harbors sufficed to receive his leviathan, loaded it with corn, and prese,tted the vessel, with its cargo, to Ptolemy, King of Egypt; and on arriving at Alexandria, it washauled ashore, and nothing more was recorded respecting it. Taking these di,nensions as the basis for calculating the tonnage, by lhe old law, or builders' measurement, and, in accordance with the report of the late Tonnage Committee, taking the average tonnage of ships as amounting to twenty-seven hundredths of the external bu]k, measured to the medium height of the upper deck, the burthen and cubic content of these vessels will be-Tonnage. External bulk. Ptolommus Philopater's ship = 6,445 tons, 8;30,700 cubic feet. ~'oah's Ark, ~ 11,905 " 1,580,000 " and contrasting with these a few modern ships: Great Western, ~ 1,242 " 161,100 " Great Britain, . . ---__ 3,445 " 446,570 " Arctic (American paekct), ~ ~,745 " 356,333 " Hymalaya, ~ 3,528 " 45'7,232 " and, calculating by the same rules, taking the dimensions given in the prospectus of the Eastern Steam .Navigation Company, their Proposed iron ship, ~ 22,942 tons, 2,973.593 cubic lbct.
It was, however, stated that this vessel was intended to be 10,000 tons register, which might be correct, if it was built on the cellular system, and was measured internally, by the present law. This latter example '*From tile London Mechanics' Magazine, ~'ovember, 1853.
61
their attendance at ye time and place aforesaid; and it was further ordered that both partys have liberty to bring with them councill learned if they ])lease."
On the Progress and Present State of the Electric Telegraphs.* The explanation ,~-hich we gave ia our last Journal of the remarkable ~,nprove ments,, in the electric, tele gra.ph has attracted. ,very general attenlioz~, and the prospectus of the Umversal Electric ~lelegraph Company is now before the public, under a highly influential directory. As the subject is one of intense scientific interest, as well as of great national importance, we this day devote our columns to a further elucidation (if the progress and present state of that art. The electric telegraphs at present in operation may be divided into four elasses~First, those the pointers o~"indices of which move in front of dials bythe agency of the electric current inside or beneath them. Second, those the indications of which'are marked by the breaking up of a continuous line, and dividing it in~,oshort and long lines and spaces. Third, telegraphs showing letters, in which a pointer on a dial is made, by the agency of' electricity beneath or behind the dial, to give motion to a wheel governed by an escapement, and then to a hand in front of the dial. Fourth, letter or type-printing telegraphs, in which the letter or metallic type is brought to a position, and while there made to impinge on paper, or otherwise to give the impression. In the first class may be placed Cooke's and Wheatstone's telegraph, as used by the Electric Telegraph Company ; Itighton's , as used by the British Telegraph Company ; Itenley's and t oster's, as used by theIrish Magnetic Telegraph Company; Deering's, as used by the Submarine and European ~lel%,raph • O" Company ; and Allen's, as proposed to be used by ~he United Kingdom Telegraph Company. The second class embraces Bain's Telegraph, as used by the General Telegraph Company on a few of their principal lines, the paper on which the line is made being ia {his plan saturated with a metallic solution ; and Morse's, used in America, in which plain paper is employed, and which is now introduced by the British Telegraph Company on some of their lines, in preference to the pointer telegraph of Itighton, previously.referi~ed to. To these pay be added Bakewell's copying telegraph, winch, oy a series ot oroK.en lines placed one under the other, leaves the letter indicated, or rather omitted, by the spaces in the broken lines. In the third class may be placed Wheatstone's orioinal~ teler,raoh,~ , now belo~ing, v to the Electric Telegraph Company; Highton's, to the Briush 2elegraph Company; Gamble and Nott's, to the Electric Telegraph Company; Allen's, proposed to be used by the United Kingdom Telegraph Company; and others of less note. The dial system is, however, subject to this objeelion, that when the hand is standing at O, or what ought to be the starting point, it must, in order to spell a word, traverse or pass over other letters on the dial, yarying in distance according to the position of the word in the alphabet, and this it must do in spelling every word. Under ~' :From the London tlailway and Commercial Gazette, No. 952. Vo~.. X X V I I . ~ T t I I a D S~:~I~s,--No. 1.--Ja-'~uaxt, 1854.
6
6"2
.Mechanics, .Physics, and Chemist~'y.
the fourth class, the letter or type-printing telegraphs~ must be classed Brett's telegraph, belonging to the Submarine Telegraph Company, and House's, as in use in Amertca. The advantages of tlm new telegraph now proposed to be worked by the Universal Electric I elegraph Company over the telegraphs comprised in the first class are, that the signals or indications corresponding with the movement of the needles or pointers are made and marked legibly and distinctly, so rapidly that needles or pointers movin/ at the same rate could not be read by the most experienced operator. To this must, of course, be added the incalculable advantage of having the communication fixed and recorded on paper, instead of the mere flickering and fleeting movements of pointers. In the first instance, the operation may be carried on with a rapidity never contemplated in former telegraphs ; and in the second instance, the communication is permanent, and may be kept and proved in years after, like a short-hand writer's note, by any person master of the alphabet. A further marked sut~eriority consists in this--that in all telegraphs worked on the .principle of the first class, one operator is required in the first instance to read the motions of the pointers, and another at the same time to write them do~vn. In the new telegraph only one operator will be required, who will write down the several communications as they appear on the paper before him, and at the same time ; and thus there is a saving of one-half of the staff of operators. Telegraphs of the second class presented certain advantages--namely, rapidity, simplicity, and clearness of character. Bain's telegraph consisted of an iron pointer or stilus, pressed upon paper saturated and kept moist with a metallic solution. Marks are made upon the paper by the passage of the electric current from any distance through the stilus, and consequently through paper in its passage to lhe earth, acting upon or decomposing both the iron stilus and the solution on tile paper, and leaving alter it a dark mark. By this system it is evident that if the current is continuous through the wire, and the paper be drawn regular]y under the stilus, the result will be a dark line ; and if the current be passed irregularly and in pulsations, the line will be broken ; anti when the current ceases to pass along the wire, no mark whatever will appear. The principle of Morse's telegraph is nearly similar; but instead of a metallic pointer acting chemically, and being in its turn chemically acted upon, this invention is a mechanical telegraph, giving precisely similar results. A lever is used, being depressed at one end and raised at the other, while the current is passing through a magnet at one extremity. A pin is placed at the raised end of the lever, which scratches the paper on contact, while the current is l~assine, and the ~)aner movino, under the pm end of the lever. If the current ~s'passmg m t;ulsations,~the line is of course broken ; and when the current ceases to pass through the magnet, the line also ceases to appear. The only form of cipher or character which these telegraphs can represent is short or long lines~thus one short line may be called a, two short lines b, three short lines c, one long line D, two l~], three I#, so that to obtain 30 lettersor conventional signs, a greater number of long or short lines, or of both, have to be used. Increased rapidity will be secured by the new telegraph from the eircum-
~lectric Telegraphs.
63
stance, that instead of one short pulsation or dot, representing one letter, it will represent two letters, two will represent four, and so on ; and the same with continuous lines, so that with one, two, and three short pulsa., fions, and one, two, and three long pulsations, instead of making, as in 5:[orse and Bain's telegraphs, only six signs or letters, twenty-eight or more can be made, thus exeeeding the whole alphabet. It is evident, therefore, that instead of seeking other and longer combinations, as must be the case with the other telegraphs, the new company will be enabled to make all necessary combinations with the newly invented telegraph. Simplicity is secured by the new telegraph using paper that does not require any preparation, either chemical or mechanical, and that is only one-fourth of the expense of that required for Morse's telegraph. Clearness is obtained by the length and size of the distinguishing characters; for instance, one short pulsation of either Morse's or Bath's telegraph makes a dot or short line of about one-sixteenth of an inch long. In the new telegraph, a similar pulsation will make a character resembling a V, or angular or arrow-pointed form, having a base about the same length as the short line above specified, and a depth in the sides of an eighth of an inch, being therefore much more distinct. Another sut)eriority, known chiefly or only to telegraphers themselves, exists ; for in consequence of the characters presenting a continuous line, and there being only suiiicient distinguishing space left between them, they are not subject to the same defects, or likely to be read wrong, as constantly occurs m other telegraphs. No comparison need be made with the third class: they are admitted to be so inferior to telegraphs of the tirst and second class; depending on an irregular vibrating movement, the slightest casual irregularity or fluctuation entails the certainty of mistake in the entire word or message. The advantages of the improved system over telegraphs of the fourth el.ass are numerous. Although the public are apt to be attracted and. misled by the supposed benefits to be derived from the telegraphs printing the letters in Roman and other readable type, there are more imperfections attending this class than are generally supposed, and which are known only to operators themselves. They depend, like those of the third class, upon a fluctuating movement of an escape-wheel, governed by an escapement, which may possibly, and often does, pass one too many, or one too few. As the type is a fixture on the wheel motion, when such a mistake occurs, the receiver must know from the sense or nonsense of what he receives by the telegraph that something is ,a,rong with the machinery ; by no means an uncommon occurrence. Perhaps the best, or, notwithstanding its extreme complexity, the most efficient telegraph of flats class, is the American one of Mr. Itouse. Even when used under his own eye, it appears to be liable to serious mishaps, and would seem to be inferior in rapidity to either Morse's or Bath's telegraphs, which are of the second class. In the telegraphs of the fi)urth class, the current transmitted along the wire has to bring into operation certain complicated apparatus or m a ' chinery, upon the correct movement of which depends the accurate transmission of the message. The superiority of the Universal Compa-
64
.Mechanics, Physics, and Clzeraistry.
ny's Telegraph over the last mentioned class consists in simplicity, corn. paralively less cost, more rapid!ty, and no necessity tor correcting errors, au even a mistake ia one letter Is not entailed on the one that follows it.
Ocean Steamers.* The discussion upon the Paper on "Ocean Steamers," by Mr. Andrew ]h:uderson, Assoc. Inst. C. E., was commenced by quoting fi'om an article in the Edinbt~rffhJo~r~zal,by Professor Tennant, of St. Andrews, the dimensions of some of the la,'ge ships built by the ancients; whence it appeared that a ship, constructed by Ptolommus Philopater, was 420 feet long, 5fJ feet b~oad, and 7"2 feet high from the keel to theprow; and was manned by fi~u," thousand rowers, four hundred servants, and two thou.~md eight hundred and twenty marines. Hiero, King of Syracuse, caused to he built, by Arehias, the Corinthian shipwright, under the supervision ,~f Archimedes, a vessel which appeared to have been armed for war, and sumptuously fitted for a pleasure yacht, and yet was ultimately used to ,:arty corn; the dimensions were not recorded, but as there were twenty banks of oars, and three masts,--the timber for the mainmast, after being in vain sought for in Italy, being brought from England,--and the cargo was sixty thousand measures of corn, besides vast quantities of provisions, &c., for the crew, the dimensions must have exceeded those of any ships cJf the present day; indeed, Hiero, finding that none of the surrounding harbors sufficed to receive his leviathan, loaded it with corn, and prese,tted the vessel, with its cargo, to Ptolemy, King of Egypt; and on arriving at Alexandria, it washauled ashore, and nothing more was recorded respecting it. Taking these di,nensions as the basis for calculating the tonnage, by lhe old law, or builders' measurement, and, in accordance with the report of the late Tonnage Committee, taking the average tonnage of ships as amounting to twenty-seven hundredths of the external bu]k, measured to the medium height of the upper deck, the burthen and cubic content of these vessels will be-Tonnage. External bulk. Ptolommus Philopater's ship = 6,445 tons, 8;30,700 cubic feet. ~'oah's Ark, ~ 11,905 " 1,580,000 " and contrasting with these a few modern ships: Great Western, ~ 1,242 " 161,100 " Great Britain, . . ---__ 3,445 " 446,570 " Arctic (American paekct), ~ ~,745 " 356,333 " Hymalaya, ~ 3,528 " 45'7,232 " and, calculating by the same rules, taking the dimensions given in the prospectus of the Eastern Steam .Navigation Company, their Proposed iron ship, ~ 22,942 tons, 2,973.593 cubic lbct.
It was, however, stated that this vessel was intended to be 10,000 tons register, which might be correct, if it was built on the cellular system, and was measured internally, by the present law. This latter example '*From tile London Mechanics' Magazine, ~'ovember, 1853.